Viral infections in human beings can be difficult to treat effectively. Indeed, if left unchecked, certain viruses can result in cancer and death. For example, it has been estimated that about twenty percent (20%) of all cancer deaths in women worldwide are from cancers which are associated with the Human Papilloma virus (HPV). It has also been estimated that 90% of all cervical cancer is linked to HPV. While the HPV virus is not the only virus that is linked to cancer or that presents significant treatment difficulties, consideration of the HPV virus provides an excellent backdrop for a discussion of the present invention.
So far, more than fifty-six (56) types of HPV virus have been identified by cloning of the HPV DNA and by hybridization techniques. The HPV virus causes genital warts and is very contagious. It is estimated that there are currently somewhere in the neighborhood of tens of millions of women who suffer from HPV infection of the genital tract. Many of these women end up developing cancer of the cervix and there is no specific therapy which is effective to cure an HPV infection. Currently, HPV is treated with applications of podophyllum, cryotherapy, antibiotics, laser surgery, etc. However, none of these therapies have been found to be satisfactory in eradicating the virus.
It has been known in the medical arts that heat kills microbes and cancer cells. There are cases reported where cancers have disappeared after the development of a high fever. Heating the entire body artificially (total body hyperthermia) has been used as a treatment employing various methods, such as immersing the body in hot water or hot molten wax, or exposing the body to radiant heat. However, total body hyperthermia is mainly limited to use as a treatment of last resort for terminal cancer patients because of the very substantial risk to the patient of death from elevated body temperature. Indeed, total hyperthermia treatment brings to mind the old joke that the operation was a success except that the patient died.
In 1990, much media attention was focused on efforts to cure patients afflicted with deadly Acquired Immune Deficiency Syndrome (AIDS), which is known to be viral, by extracorporeal circulation (heating the blood outside of the body). Successful results of such efforts will likely be limited by the fact that the AIDS viruses are known to reside in many other parts of the body besides the bloodstream. Thus, this approach to the AIDS problem fails to treat significant components of the AIDS virus in the body.
Laser beams, microwave energy and other heating methods have been used locally to kill tumors rather than heating the entire body. However, these techniques also tend to damage healthy tissue. Typical known local heating devices kill at the site of contact and are adapted for either treating external cancers or for treating a specific limited situs of a cancer inside the body. These devices are poorly suited to heating entire hollow organs to eliminate viruses. This is so because the devices generally are not adapted for heating the hollow organ for a long period of time, as may be necessary to kill viruses, and are not well suited to treating the complex and often extensive surfaces of hollow organs safely. For example, there are presently no known devices or methods for heating the esophagus to kill esophageal cancer cells.
In a recent study, 24 women with subclinical HPV infection were treated with an extensive CO.sub.2 laser procedure wherein the epithelium (the surface layer of the mucous membrane) of the entire lower genital tract was vaporized. This procedure was costly and quite painful for the patients and resulted in many complications. Only one of the 24 patients was cured of the HPV infection.
Accordingly, it can be seen that a need remains for a method and apparatus for treating viruses and cancers in hollow organs and orifices by heating the infected or cancerous cells, while minimizing pain, collateral injury to surrounding tissue, and the risk of death. It is to the provision of such a method and apparatus that the present invention is primarily directed.